[CentOS] question on kernel compile

I "think" I followed the directions on kernel compile (actually I 
downloaded 2.6.21.5).
did the make oldconfig, did make menuconfig, did my compile and 
everything is working fine
in that regard.

My question now is how do I take that kernel configuration and use it 
for another machine
that also needs the 2.6.21.5 kernel. Basically I am trying to save the 
step of going back into
menuconfig and reselecting what I wanted.

Thanks,

Jerry